Apparatus and method for cutting trees

ABSTRACT

A tree cutter in combination with a self-propelled vehicle is disclosed for cutting underbrush and small free standing trees, such as, Cedar. The tree cutter is pivotally mounted at the front of the self-propelled vehicle, such as, a Four Wheeler in order to pivot upon a horizontal axis. The tree cutter provides a frame assembly that includes a discrete pair of triangular straight edge blades followed by a pair of circular blades that rotate in opposite directions caused by contact with the inner core the tree. The blade pairs are adjacent, oppositely disposed, and selectivly spaced apart as included in the frame assembly.  
     The blade pairs act in synergy as they are driven into the tree by the vehicle, wherein the straight blades are suited for slicing into the soft outer vascular core of the tree, thereafter shearing force of the rotating blades is applied to the harder sapwood and heartwood that are engaged between the rotating blades.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to clearing land of treesefficiently, especially small trees with a thickness of up to seveninches in diameter, such as Cedar, without the use of expensiveself-propelled machinery, such as tractors, bulldozers and the like. Itis therefore an object of the invention to provide an effective, yetrelatively inexpensive cutting tool that can be easily mounted anddismounted from a small self-propelled vehicle, such as, a Four Wheelercreating a dual purpose vehicle. Among the several objects of theinvention, therefore, is to eliminate the need for using heavy equipmentthat has more capacity than needed for the job. It is a further objectof the invention to provide a system of replaceable smooth flat bladesthat are task specific for cutting the softer outer core and the harderinner core of a tree, providing an efficient means for cutting.

SUMMARY OF THE INVENTION

[0002] According to the invention, two pairs of blades each pair beingoppositely disposed are mounted within the interior of a fork-like frameassembly that is pivotally attached to the bottom frame of aself-propelled vehicle preferably a Four Wheeler by means of a tubeassembly. The frame assembly is positioned in front of the Four Wheelerand suspended by a cable attached to the top of the frame assembly atone end and, at the other end, wound upon a self-propelled winch that isstandard equipment on many Four Wheelers. By adjusting the length of thecable the tree cutter is allowed to pivot against the frame of thevehicle so that the frame assembly can be lowered nearer to the groundfor cutting smaller trees and underbrush and raised to cut largerfree-standing trees.

[0003] A first pair of anterior straight edge blades are provided forslicing the outer core of the tree, driven by the forward motion of theself-propelled vehicle. They are followed by a pair of circular bladesthat rotate freely in counter-rotation to each other upon contact withthe inner core as the vehicle continues its forward motion against thetree. The rotational blades are spaced closer together than the straightedge blades in order to pinch the remaining inner core by theirsimultaneous counter-rotational motion. Thus, the cutting pressureapplied by the rotational blades is greater and more suited for cuttingthe denser, harder sapwood and heartwood of the inner tree core. This isbecause the cutting edge of the rotational blades are driven into thetree wood as they rotate, cutting by shearing force rather than byslicing as performed by the first pair of straight edge blades.

[0004] Optionally, a single additional straight edge blade is laterallymounted behind the pair of rotational blades at the extreme interior ofthe frame to clear any remaining debris after the inner core of the treehas been cut. All blades are removable for maintenance and replacement.In addition, the space between the rotational blades is adjustable toachieve optimum cutting efficacy and to account for blade wear andvariations in tree thickness.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIG. 1 is a perspective view of the tree cutter of the invention.

[0006]FIG. 2 is a top elevational view of the preferred tree cutter.

[0007]FIG. 3 is a top elevational view of the bottom plate of the treecutter frame assembly.

[0008]FIG. 4 is a perspective view of the circular blade adjustmentmeans.

[0009]FIG. 5 is a schematic view of the tree cutter assembly.

[0010]FIG. 6 is a top elevational view of an alternate embodiment of theframe assembly.

[0011]FIG. 7 is a side view of the frame assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

[0012] Referring to FIGS. 1 and 2 a tree cutter 10 includes afork-shaped frame assembly 12 including two identical forward divergingframe members 32. A tube assembly 44 attaches frame assembly 12 to theframe of a self-propelled vehicle and pivots upon axis 68. The frameassembly can be raised or lowered by cable 58 attached at one end toframe assembly 12 at grommet 56, the other end being wound upon a winchmounted to the self-propelled vehicle. Forward diverging members 32 formthe interior of the frame 12 which includes a first pair of straightedge blades 14 that are stationary and spaced apart opposite each other.Oppositely slanted cutting edges 16 and 16 a provide for cutting by theforward and backward movement of the self-propelled vehicle. Thus, afteredge 16 initially engages the tree T, cutting can also be performed bythe backward motion of the vehicle, engaging cutting edge 16 a slantedtoward the interior of the frame 12. The backward cutting avoidsuprooting tree T causing messy debris according to the prior art methodsif edge 16 is initially snagged. Preferably, edges 16 and 16 a areconnected by arcuate edge 20. A second pair of oppositely disposedcircular blades 22 are mounted to frame 12 behind blades 14 so that theycan rotate freely in opposite directions when contact is made with treeT. No power is applied to blades 22, as according to the prior art,except the force provided by the motion of the self-propelled vehiclecausing the frictional engagement of blades 22 with tree T. Asillustrated in FIG. 2, blades 22 are spaced closer together than blades14 for engaging the inner core 74 of tree T.

[0013] Fame assembly 12 includes a bottom plate 30 (FIG. 3) that isoverlaid by a top plate 28. The plates are held together by carriagebolts extending from underneath the bottom plate 30 through pre-drilledholes 66 in both plates and secured by hexagonal nuts positioned at thetop plate 28. Blade pairs 14 and 22 are connected to the frame assembly12 inside a housing formed between the top and bottom plates. FIG. 3shows the interior surface of bottom plate 30 with blade pairs 14 and 22attached before overlaid by the top plate 28. Spacers 62 provide theproper space between the top plate 28 and bottom plate 30 so that blades22 can freely rotate in the housing between the plates. Circular blades22 rotate freely on bushing 76 that is sandwiched between the top andbottom plates and will not move during operation, being compressed bythe assembly of plates 30 and 28. However, the circular blades aredimensioned so they can rotate. Accordingly, circular blades 22 includea centered hole that is 1¼ inches in diameter into which bushing 76 isinserted. Because bushing 76 has an outside diameter of 1 and {fraction(1/16)} inches, there is a preferable {fraction (3/16)} inch clearancefor each blade 22 to rotate on bushing 76.

[0014] Each blade 22 is secured by carriage bolt 78 that beginsunderneath bottom plate 30 at slot 26 and extends through the center ofbushing 76 and through identical slot 24 of top plate 28 shown in FIGS.2 and 3. As illustrated in FIG. 4, carriage bolt 78 is secured byhexagonal nut 94 that sits on bushing 80 atop plate 28. The center ofrotation of the circular blades can be changed by turning bolt 82against bushing 80. This will laterally reposition the carriage bolt 78through slots 24 and 26 of the top and bottom plates respectively. Thenet effect is to reposition the circular blades 22 and to enlarge ordiminish the space between them. Blades 14 and 22 are preferably madefrom “D-2” steel having a “Rockwell Hardness” of between 58 and 60.

[0015] To provide for structural integrity of frame assembly 12, bottomplate 30 includes a peripheral lip 42 (FIG. 3) that does not extend tothe interior of the frame assembly 12. This is to allow blade pairs 14and 22 to protrude from the frame assembly 12 into the space included bythe frame assembly 12. Top plate 28 is slightly smaller than bottomplate 30 and includes a peripheral lip 40 that does extend into theinterior of frame assembly 12. When the plates are attached, lip 40 fitsinside and snug against lip 42 illustrated in FIG. 2. In order toenhance the structural design of the frame assembly 12, top plate 28also includes ribs 36, extending the length of frame members 32, lateralrib pairs 38, medial rib pairs 38 a and lateral rib 70 illustrated inFIGS. 2 and 7. Forward diverging frame members 32 include tapered ends34 shown in FIG. 7 so they can function like skids while cuttingunderbrush and small trees at ground level.

[0016] Referring to FIGS. 2 and 5 tube assembly 44 attaches to the frameof the vehicle allowing the tree cutter 10 to pivot on the horizontalaxis 68 and allowing the frame assembly 12 to extend forward of thevehicle during operation. The frame assembly 12 is mounted to the tubeassembly 44 by attaching horizontal tabs 46 to the posterior end of ribs36 as illustrated in FIG. 5. At the opposite end, tube assembly 44attaches to the vehicle mounting plate assembly 84 by inserting verticaltabs 52 into the stalls under plate assembly 84 and inserting pin 88thorough holes provided at the stalls and the vertical tabs 52, so thatthe tree cutter 10 can pivot on horizontal axis 68 as illustrated inFIG. 5. Vehicle frame assembly 84 attaches underneath vehicle framemembers 90 by means of bolt assembly 86 as also illustrated in FIG. 5.Tubes 48 extend underneath and forward of the vehicle for attachment ofthe frame assembly 12. Lateral tubes 50 provide structural support.Included with tube assembly 44 is a tapered bumper guard 54 and grommet56 for attachment of the suspension cable 58 shown in FIG. 1. A safetyguard 64 is provided for the vehicle operator and attaches to verticaltabs 60 illustrated in FIG. 5.

[0017]FIG. 6 illustrates modification 18 of the first pair of blades toform a triangle and modification of the frame assembly 12 to include astraight edge blade 92 mounted at the extreme interior of frame assembly12.

[0018] In use, tree cutter 10 accounts for the disparate cross-sectionaldensities of the trunk of tree T. The outer bark (periderm), inner bark(secondary phloem), and vascular cambium is defined herein as the softerouter core of tree T. Contained within the outer core is the inner coreof tree T comprised of the denser regions of the sapwood and heartwoodwhere the tree's resin has become hard (Website: Texas Education Agency,(http://levftn.vfm.orglprojects/chalfant/biology.htm). The straight edgeblades 14 will first slice into the outer core 72 as the vehicle thrustsinto the tree T (FIG. 1), leaving the remaining inner core 74 forcutting by means of the shearing force of the rotational blades 22.Shearing force means the final cut when the inner core is pinchedbetween the simultaneous counter-rotation of blades 22. Straight edgeblades 14 are well suited for cutting the softer bark and vascularregions of outer core 72, while rotational blades 22 are more effectivein bringing greater cutting pressure to bear upon the denser inner core74 of tree T. Thus, the straight edge blades 14 and rotational blades 22act in synergistic relationship rendering remarkably clean cutting.

[0019] By raising and lowering the frame assembly 12 by adjusting thelength of the suspension cable 58 cutting, ranging from undergrowth andsmall trees to larger free-standing trees, can be performed in oneclearing operation. Moreover the tree cutter 10 can be easily dismountedfrom the vehicle by disengaging bolts 86 (FIG. 5). The top plate 28 ofthe frame assembly 12 can be easily removed for cleaning the framehousing and blades 22 and 14.

[0020] The invention has been described with reference to the preferredembodiment. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the invention be construed as includingall such modifications and alterations insofar as they come within thescope of the appended claims or the equivalents thereof.

I claim:
 1. An improved tree cutter in combination with a self-propelledvehicle wherein said tree cutter is pivotally mounted to said vehiclewith adjustable suspension means for pivotal movement of said treecutter about a horizontal axis, the improvement comprising: a frameassembly including discrete cutting means extending forward of saidvehicle, said cutting means including a combination of a first pair ofreplaceable straight edge blades and adjacent thereto a second pair ofreplaceable circular blades that rotate oppositely caused when contactis made with the trunk of a tree, wherein the blades of each pair areoppositely disposed and spaced apart on the same plane included by saidframe assembly, each blade of said first pair having oppositely slantedcutting edges that are joined and attached to said frame assembly sothat they are stationary, said second pair of circular blades beingadjustably attached to said frame assembly for changing the distancebetween said circular blades, said distance being shorter than thedistance between said oppositely disposed straight edge blades.
 2. Theimproved tree cutter as claimed in claim 1 wherein said frame assemblyincludes a top plate and a bottom plate detachable therefrom forming aframe housing including two forward diverging frame members wherein saidfirst and second pair of blades are mounted to said frame members insidesaid frame housing.
 3. The improved tree cutter as claimed in claim 2wherein the extreme end of each said forward diverging frame member istapered upward.
 4. The improved tree cutter as claimed in claim 2wherein the top surface of each said frame member includes alongitudinal rib extending the length of said frame member and at leasttwo pairs of lateral ribs that intersect each said longitudinal rib. 5.The improved tree cutter as claimed in claim 2 wherein said frameassembly is pivotally mounted to said vehicle by means of a detachabletube assembly.
 6. The improved tree cutter as claimed in claim 5 whereinsaid tube assembly includes an arcuate bumper guard that is laterallyfixed with respect to said forwardly diverging frame members.
 7. Theimproved tree cutter as claimed in claim 5 wherein said tube assemblyincludes a detachable protective barrier that extends perpendicularlytherefrom to above said vehicle.
 8. The improved tree cutter as claimedin claim 6 wherein said adjustable suspension means is removablyattached to said arcuate bumper guard.
 9. The improved tree cutter asclaimed in claim 1 wherein said oppositely slanted cutting edges arejoined directly together to form the sides of a triangle.
 10. Theimproved tree cutter as claimed in claim 1 wherein said oppositelyslanted cutting edges are jointed by an arcuate cutting edge.
 11. Theimproved tree cutter as claimed in claim 1 wherein said cutting meansincludes a straight edge mounted at the extreme interior of said frameassembly.
 12. A method of cutting trees, comprising driving acombination of discrete cutting means into a trunk of a tree by means ofa self-propelled vehicle for selectively engaging the disparatedensities of a light outer core and a hard inner core of said trunk on asame substantially horizontal plane by slicing said outer core by meansof a first pair of stationary straight edge blades oppositely disposedand spaced apart by attachment to a support means that is mounted to thefront of said self-propelled vehicle, each blade of said first bladepair being formed from oppositely slanted cutting edges that are joined;then applying shearing force to said inner core by means of a secondpair of oppositely disposed circular blades that are caused tooppositely rotate when contact is made with said inner core, saidcircular blades being adjustably attached to said support means forchanging the distance between said circular blades, said distance beingshorter than the distance between said oppositely disposed first bladepair.
 13. The method of cutting trees as claimed in claim 12 whereinsaid oppositely slanted cutting edges are joined directly together toform the sides of a triangle.
 14. The method of cutting trees as claimedin claim 12 wherein said oppositely slanted cutting edges are joined byan arcuate cutting edge.
 15. The method of cutting trees as claimed inclaim 12 wherein said discrete cutting means includes a straight edgeblade attached to said support means for clearing debris after saidshearing force has been applied.